But I still do not get anything other than 0 displayed even through the event log shows it as 0.032. So I’m either doing something wrong with the format, or the device.energy value doesn’t allow formatting, or something else I’ve not considered.

(and remove the unit: part). While this works for display in the app, the energy is now a string including units instead of a raw numeric value - using this in another smart app might causes problems as most likely it won’t expect a string with units…